Slubber, also known as living rubber, is a fictional, colorful substance that was conceived by artists EbonyRubberWolf and Hakusei. In essence, it is a rubbery substance that is used in the conversion of the anatomy of living furs into living toyfurs.
The concept has been mostly confined within the art posted by various individuals on Fur Affinity, although the idea of anthropomorphic beings being entirely constituted of living rubber (such as that featured in the art of rwolf) is somewhat longer lived. Slubber beings, within the fictional universe constructed by EbonyRubberWolf and Hakusei, are usually used as enslaved sex toys.
According to Rubber Zebra:
"Their hands and lower arms disapear into thier lower back and their legs fuse together. All senses but touch are gone. The only holes in the rubbe body are the mouth which is a small hole, and the anis. Both go into the body about 16 inches then dead end. Plus they both secrete a lubricant, giving you an idea for what ther purpose of a slubber is for. The collar can controll thier form, from a regular slubber being that can move, talk and such. And if you want, can change the slubber into a wriggling slave like above. They can't complain, or run away. And are forced to do whatever anyone wants.....And it's irreversable."